Background technology
Silicon sol is the nanometer silicon dioxide particle dispersion liquid in water or other organic solvent of particle diameter in 1-100 nanometer range, is widely used in precision casting, refractory materials, coating, support of the catalyst, the field such as precise polished.Silicon sol can be divided into water silica sol and organic solvent type silica sol according to the difference of its dispersion medium, and the silicon sol being wherein dispersion agent with low-boiling point alcohol (methyl alcohol, ethanol, Virahol etc.) can be applicable to the speciality coatings such as high-temperature resistant coating, damage resistant coating, aerospacecraft coating.
Silicon sol manufacturing enterprise domestic is at present a lot, but most enterprises can only produce water silica sol, does not also adopt ultrafiltration and concentration and silane hydrolyzate technique to combine to produce the correlation technique reports such as the patent of alcohol dispersed silicon colloidal sol and paper at present.
Water silica sol production technology mainly contains ion exchange method and silica flour hydrolysis method.
Ion exchange method is produced silicon sol and is mainly adopted water glass to be raw material, first water glass is mixed with the aqueous solution of 5-10%, then ion-exchange is carried out by Zeo-karb, remove sodium ion and obtain rare silicate aqueous solution, then rare silicate solution of 3-6% is added drop-wise in reactor, by the pH value of the hierarchy of control, makes silicic acid aggregate into silicon dioxide granule in the basic conditions gradually, then through concentrated, silicon sol finished product is obtained.This production technology is adopted by a lot of enterprise because cost is low, but has two shortcomings: (one) regeneration of ion-exchange resin will produce a large amount of waste water, and the concentration process in later stage also will produce a large amount of waste water, can cause more serious environmental pollution.(2) production cycle is long, and the whole production cycle needs tens hours, and production efficiency is low.
The production technique of elemental silicon hydrolysis method is fairly simple, add water in a kettle., add basic catalyst, after being warming up to suitable temp, add simple substance silica flour, silica flour is hydrolyzed under base catalysis, generates silicic acid and aggregate into silicon dioxide granule, finally filtering the silicon sol just obtaining suitable concn, the whole production cycle was less than 10 hours, and emit no waste water, filtering a small amount of waste residue produced as the raw material of refractory materials, thus can not have problem of environmental pollution.
The silicon sol that current most domestic enterprise produces take water as the silicon sol of dispersion agent with above-mentioned explained hereafter, and what market was not almost produced in batches take low-boiling point alcohol as the silicon sol of dispersion agent.
Summary of the invention
Take low-boiling point alcohol as the problem of the silicon sol of dispersion agent in order to what to solve in above prior art not batch production, the invention provides the production technique that a kind of ultrafiltration and concentration combines with silane hydrolyzate, preparing with low-boiling point alcohol is the silicon sol of dispersion agent.This patent technical problem to be solved first adopts ultra-filtration membrane concentration technology to remove most of moisture in water silica sol, be replaced as low-boiling point alcohol, then add appropriate silane to be hydrolyzed reaction, a small amount of water consumption remaining in silicon sol is fallen, thus to prepare with low-boiling point alcohol be the silicon sol of dispersion agent.
The present invention is achieved by the following measures:
A kind of preparation method of alcohol dispersed silicon colloidal sol, alcohol is added to being processed in acid water silica sol, adopt ultrafiltration concentration process to carry out being concentrated into water silica sol admittedly to contain, then pH is regulated to be 4-5, be warming up to 40-50 DEG C, in 3-4 hour, add methyl silicate, tetraethoxy or positive isopropyl silicate, in 0.5-3 hour, then add methyltrimethoxy silane or ethyl triethoxysilane to be hydrolyzed reaction.
Described preparation method, the alcohol added and the mass ratio of water silica sol are 3-4:5.
Described preparation method, in methyl silicate, tetraethoxy or positive isopropyl silicate and system, the mol ratio of water is 1:2-4, and in methyltrimethoxy silane or ethyl triethoxysilane and system, the mol ratio of water is 1:8-25.
Described preparation method, repeats to add alcohol, ultrafiltration concentration process enrichment step several times.
Described preparation method, repeats to add alcohol, ultrafiltration concentration process enrichment step 3 times.
Described preparation method, the alcohol in alcohol dispersed silicon colloidal sol is methyl alcohol, ethanol or Virahol.
Described preparation method, the film used in described ultrafiltration concentration process is polysulfone membrane, polyamide membrane or cellulose membrane.
Described preparation method, in described water silica sol, dioxide-containing silica is 20-40%, particle diameter is 10-120nm.
Described preparation method, the alcohol dispersed silicon colloidal sol dioxide-containing silica obtained is 20-40%, and moisture content is less than 1%, and stationary phase is not less than 6 months.
Described preparation method, uses storng-acid cation exchange resin general alkali silicon sol to be processed into acid water silica sol.
Beneficial effect of the present invention:
1. ultrafiltration and concentration combines with silane hydrolyzate, the most of moisture in water silica sol is first removed by ultrafiltration concentration process, be replaced as lower alcohol simultaneously, and then add appropriate silane and be hydrolyzed, a small amount of water consumption remaining in silicon sol is fallen, thus obtain water-content very low take low-boiling point alcohol as the silicon sol of dispersion agent;
2. products obtained therefrom dioxide-containing silica high (about 20-40%), moisture content very low (being less than 1%), stationary phase long (being greater than 6 months);
3. with ordinary silicon colloidal sol for main raw material, cost is low;
4. ultra-filtration membrane technique and ordinary-pressure hydrolysis reaction, production technique is simple.
Embodiment
For a better understanding of the present invention, further illustrate below in conjunction with specific embodiment.
Embodiment 1
Be 30% by dioxide-containing silica, particle diameter be the general alkali silicon sol of 10-30nm by storng-acid cation exchange resin, be prepared into the acidic silicasol of 30%.
At normal temperatures above-mentioned for 1000kg acidic silicasol is added in polysulphones hyperfiltration membrane thickener, under agitation adds first 700kg dehydrated alcohol, mix, then open thickener and concentrate; When the quality being concentrated into liquid effluent reaches 700kg, add second batch 700kg dehydrated alcohol in the feed and be uniformly mixed, then proceeding to concentrate; When the quality being concentrated into liquid effluent reaches 700kg, add the 3rd batch of 700kg dehydrated alcohol and be uniformly mixed, then proceeding to concentrate; Ultrafiltration and concentration is terminated when the quality being concentrated into liquid effluent reaches 700kg.In mensuration system, moisture content is 87.8kg(4.88kmol).
Silicon sol after above-mentioned concentrating adds appropriate glacial acetic acid and regulates pH=4-5, be warming up to 40-50 DEG C, under agitation slowly added 462kg tetraethoxy (2.22kmol) with 3-4 hour, 50kg ethyl triethoxysilane (0.26kmol) is slowly added again with 1-1.5 hour, continue hydrolysis reaction 1 hour, namely obtain moisture content lower than 1% take ethanol as the silicon sol of dispersion agent.
The aqueous solution of concentrated liquid effluent to be ethanol content be 75%-80%, can be reclaimed ethanol by distillating method.
Embodiment 2[uses methyl alcohol instead, good results]
Be 30% by dioxide-containing silica, particle diameter be the general alkali silicon sol of 30-50nm by storng-acid cation exchange resin, be prepared into the acidic silicasol of 30%.
At normal temperatures above-mentioned for 1000kg acidic silicasol is added in polysulphones hyperfiltration membrane thickener, under agitation adds first 800kg methyl alcohol, mix, then open thickener and concentrate; When the quality being concentrated into liquid effluent reaches 800kg, add second batch 800kg methyl alcohol in the feed and be uniformly mixed, then proceeding to concentrate; When the quality being concentrated into liquid effluent reaches 800kg, add the 3rd batch of 800kg methyl alcohol and be uniformly mixed, then proceeding to concentrate; Ultrafiltration and concentration is terminated when the quality being concentrated into liquid effluent reaches 800kg.In mensuration system, moisture content is 71.3kg(3.96kmol).
Add appropriate glacial acetic acid in silicon sol after above-mentioned concentrating and regulate pH=4-5, be warming up to 40-50 DEG C, then under agitation 274kg methyl silicate (1.80kmol) was slowly added with 3-4 hour, 31kg methyltrimethoxy silane (0.23kmol) is slowly added again with 0.5-1 hour, continue hydrolysis reaction 1 hour, about adding 86kg methyl alcohol adjustment concentration to 30% again, namely obtain moisture content lower than 1% take methyl alcohol as the silicon sol of dispersion agent.
The aqueous solution of concentrated liquid effluent to be methanol content be 75%-80%, can by distillating method by Methanol Recovery.
Embodiment 3[uses Virahol instead, good results]
Be 20% by dioxide-containing silica, particle diameter be the general alkali silicon sol of 20-40nm by storng-acid cation exchange resin, be prepared into the acidic silicasol of 30%.
At normal temperatures above-mentioned for 1000kg acidic silicasol is added in polysulphones hyperfiltration membrane thickener, under agitation adds first 800kg Virahol, mix, then open thickener and concentrate; When the quality being concentrated into liquid effluent reaches 800kg, add second batch 800kg Virahol in the feed and be uniformly mixed, then proceeding to concentrate; When the quality being concentrated into liquid effluent reaches 800kg, add the 3rd batch of 800kg Virahol and be uniformly mixed, then proceeding to concentrate; Ultrafiltration and concentration is terminated when the quality being concentrated into liquid effluent reaches 800kg.In mensuration system, moisture content is 101.2kg(5.62kmol).
Add appropriate glacial acetic acid in silicon sol after above-mentioned concentrating and regulate pH=4-5, be warming up to 40-50 DEG C, then under agitation the positive isopropyl silicate of 586kg (2.22kmol) was slowly added with 3-4 hour, 126kg ethyl triethoxysilane (0.66kmol) is slowly added again with 2-3 hour, continue hydrolysis reaction 1 hour, namely obtain moisture content lower than 1% take Virahol as the silicon sol of dispersion agent.
The aqueous solution of concentrated liquid effluent to be isopropanol content be 75%-80%, can by distillating method by isopropanol recovering.
When embodiment 4[concentrates, ethanol consumption is on the low side, and cause the finished product moisture content higher, effect is bad]
Be 30% by dioxide-containing silica, particle diameter be the general alkali silicon sol of 60-80nm by storng-acid cation exchange resin, be prepared into the acidic silicasol of 30%.
At normal temperatures above-mentioned for 1000kg acidic silicasol is added in polysulphones hyperfiltration membrane thickener, under agitation adds first 600kg dehydrated alcohol, mix, then open thickener and concentrate; When the quality being concentrated into liquid effluent reaches 600kg, add second batch 600kg dehydrated alcohol in the feed and be uniformly mixed, then proceeding to concentrate; When the quality being concentrated into liquid effluent reaches 600kg, add the 3rd batch of 600kg dehydrated alcohol and be uniformly mixed, then proceeding to concentrate; Ultrafiltration and concentration is terminated when the quality being concentrated into liquid effluent reaches 600kg.In mensuration system, moisture content is 109.5kg(6.08kmol).
Add appropriate glacial acetic acid in silicon sol after above-mentioned concentrating and regulate pH=4-5, be warming up to 40-50 DEG C, then under agitation 322kg tetraethoxy (1.55kmol) was slowly added with 3-4 hour, 50kg ethyl triethoxysilane (0.26kmol) is slowly added again with 1-1.5 hour, continue hydrolysis reaction 1 hour, namely obtaining take ethanol as the silicon sol of dispersion agent.
The aqueous solution of concentrated liquid effluent to be ethanol content be 75%-80%, can be reclaimed ethanol by distillating method.
Embodiment 5[does not add ethyl triethoxysilane, and stationary phase is short, and effect is bad]
Be 30% by dioxide-containing silica, particle diameter be the general alkali silicon sol of 20-40nm by storng-acid cation exchange resin, be prepared into the acidic silicasol of 30%.
At normal temperatures above-mentioned for 1000kg acidic silicasol is added in polysulphones hyperfiltration membrane thickener, under agitation adds first 700kg dehydrated alcohol, mix, then open thickener and concentrate; When the quality being concentrated into liquid effluent reaches 700kg, add second batch 700kg dehydrated alcohol in the feed and be uniformly mixed, then proceeding to concentrate; When the quality being concentrated into liquid effluent reaches 700kg, add the 3rd batch of 700kg dehydrated alcohol and be uniformly mixed, then proceeding to concentrate; Ultrafiltration and concentration is terminated when the quality being concentrated into liquid effluent reaches 700kg.In mensuration system, moisture content is 87.5kg(4.86kmol).
Add appropriate glacial acetic acid in silicon sol after above-mentioned concentrating and regulate pH=4-5, be warming up to 40-50 DEG C, under agitation slowly added 506kg tetraethoxy (2.43kmol) with 3-4 hour, continue hydrolysis reaction again 1 hour, namely obtain moisture content lower than 1% take ethanol as the silicon sol of dispersion agent.
The aqueous solution of concentrated liquid effluent to be ethanol content be 75%-80%, can be reclaimed ethanol by distillating method.
Embodiment 6[particle diameter 60-80nm content 35%, good results]
Be 35% by dioxide-containing silica, particle diameter be the general alkali silicon sol of 60-80nm by storng-acid cation exchange resin, be prepared into the acidic silicasol of 35%.
At normal temperatures above-mentioned for 1000kg acidic silicasol is added in polysulphones hyperfiltration membrane thickener, under agitation adds first 650kg dehydrated alcohol, mix, then open thickener and concentrate; When the quality being concentrated into liquid effluent reaches 650kg, add second batch 650kg dehydrated alcohol in the feed and be uniformly mixed, then proceeding to concentrate; When the quality being concentrated into liquid effluent reaches 650kg, add the 3rd batch of 650kg dehydrated alcohol and be uniformly mixed, then proceeding to concentrate; Ultrafiltration and concentration is terminated when the quality being concentrated into liquid effluent reaches 650kg.In mensuration system, moisture content is 81.6kg(4.53kmol).
Silicon sol after above-mentioned concentrating adds appropriate glacial acetic acid and regulates pH=4-5, be warming up to 40-50 DEG C, under agitation slowly added 422kg tetraethoxy (2.03kmol) with 3-4 hour, 40kg ethyl triethoxysilane (0.21kmol) is slowly added again with 1-1.5 hour, continue hydrolysis reaction 1 hour, namely obtain moisture content lower than 1% take ethanol as the silicon sol of dispersion agent.
The aqueous solution of concentrated liquid effluent to be ethanol content be 75%-80%, can be reclaimed ethanol by distillating method.
Embodiment 7[particle diameter 80-100nm content 40%, good results]
Be 40% by dioxide-containing silica, particle diameter be the general alkali silicon sol of 80-100nm by storng-acid cation exchange resin, be prepared into the acidic silicasol of 40%.
At normal temperatures above-mentioned for 1000kg acidic silicasol is added in polysulphones hyperfiltration membrane thickener, under agitation adds first 600kg Virahol, mix, then open thickener and concentrate; When the quality being concentrated into liquid effluent reaches 600kg, add second batch 600kg Virahol in the feed and be uniformly mixed, then proceeding to concentrate; When the quality being concentrated into liquid effluent reaches 600kg, add the 3rd batch of 600kg Virahol and be uniformly mixed, then proceeding to concentrate; Ultrafiltration and concentration is terminated when the quality being concentrated into liquid effluent reaches 600kg.In mensuration system, moisture content is 75.7kg(4.21kmol).
Add appropriate glacial acetic acid in silicon sol after above-mentioned concentrating and regulate pH=4-5, be warming up to 40-50 DEG C, then under agitation the positive isopropyl silicate of 490kg (1.86kmol) was slowly added with 3-4 hour, 49kg ethyl triethoxysilane (0.26kmol) is slowly added again with 1-1.5 hour, continue hydrolysis reaction 1 hour, namely obtain moisture content lower than 1% take Virahol as the silicon sol of dispersion agent.
The aqueous solution of concentrated liquid effluent to be isopropanol content be 75%-80%, can by distillating method by isopropanol recovering.
The silicon sol product index obtained in above-described embodiment is as following table:
|
Water-content |
Dioxide-containing silica |
Dispersion agent |
Stationary phase (moon) |
Embodiment 1 |
0.2% |
29.5% |
Ethanol |
≥6 |
Embodiment 2 |
0.1% |
30.3% |
Methyl alcohol |
≥6 |
Embodiment 3 |
0.3% |
20.2% |
Virahol |
≥6 |
Embodiment 4 |
4.8% |
29.8% |
Ethanol |
≥6 |
Embodiment 5 |
0.3% |
29.4% |
Ethanol |
1-2 |
Embodiment 6 |
0.1% |
35.1% |
Ethanol |
≥6 |
Embodiment 7 |
0.2% |
39.9% |
Virahol |
≥6 |